<template>
	<view class="u-wrap">
		<!-- 搜索框 -->
		<view class="u-search-box">
			<u-search placeholder="请输入搜索内容" v-model="search_keyword" @custom="searchGoods"></u-search>
		</view>
		<!-- 标题栏 -->
		<view class="u-menu-wrap">
			<scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop">	
				<template v-for="topGoods in tabbar" >
					<!-- <view class="u-tab-item u-tab-title">
						<text>{{topGoods.name}}</text>
					</view> --> 
					<u-collapse :head-style="headstyle">
							<u-collapse-item :title="topGoods.name" :open="true" >
								<view
									v-for="childGoods in topGoods.children" 
									:key="childGoods.id" class="u-tab-item" 
									:class="[current==childGoods.id ? 'u-tab-item-active' : '']"
									:data-current="childGoods.id" 
									@tap.stop="swichMenu(childGoods.id)
									">
								  <text class="u-line-1">{{childGoods.name}}</text>
								</view>
							</u-collapse-item>
						</u-collapse>
					
				</template>
			</scroll-view>
			<!-- 商品栏 -->
				<scroll-view scroll-y class="right-box"  @scrolltolower="updataGoods" @search="updataGoods">
					<view class="page-view">
						<view class="class-item">
							<view class="item-container">
								<view class="thumb-box" v-for="goods in goodsList" :key="goods.id">
									<navigator class="u-text-center goods_item" :url="'/pages/goods/goods?id='+goods.id">
										<image class="item-menu-image" :src="goods.cover_url" mode=""></image>
										<view class="item-menu-name">{{goods.title}}</view>
									</navigator>
								</view>
								<template v-if="!isNoGoods">
									<!-- 无商品提示 -->
									<u-alert-tips type="warning" title="很抱歉没有更多商品"></u-alert-tips>
								</template>
							</view>
						</view>
					</view>
				</scroll-view>
		</view>
	</view>
</template>

<script>
	
	export default {
		async onLoad() {
			this.getGoodsList()
		},
		data() {
			return {
				goodsList:[],
				tabbar: [],
				scrollTop: 0, //tab标题的滚动条位置
				current: 0, // 预设当前项的值
				menuHeight: 0, // 左边菜单的高度
				menuItemHeight: 0, // 左边菜单item的高度
				search_keyword:"",
				page:1,
				category_id:0,
				isNext:true,
				isNoGoods:0,
				headstyle: {
					marginLeft: '40rpx',
					fontWeight:900,
					fontSize:"30rpx"
				}
			}
		},
		computed: {
			
		},
		methods: {
			async searchGoods(){
				//搜索商品
				this.category_id = 0
				this.page = 1
				this.getGoodsList()
			
			},
			updataGoods(){
				if(!this.isNext) return
				//获取更多数据
				this.page = this.page+1
				this.getGoodsList()
			},
			async getGoodsList(){
				//请求商品列表
				const params = {
					title:this.search_keyword,
					page:this.page,
					category_id:this.category_id,
				}
				const {categories,goods} = await this.$u.api.getGoodsList(params)
				
				if(this.page === 1) this.goodsList = goods.data
				else this.goodsList = [...this.goodsList,...goods.data]
				this.tabbar = categories
				this.isNext = goods.next_page_url
				//根据返回的商品列表长度判断是否有商品
				this.isNoGoods = this.goodsList.length
			},
			getImg() {
				return Math.floor(Math.random() * 35);
			},
			// 点击左边的栏目切换
			async swichMenu(id) {
				if(id == this.current) return ;
				this.current = id;
				// 如果为0，意味着尚未初始化
				if(this.menuHeight == 0 || this.menuItemHeight == 0) {
					await this.getElRect('menu-scroll-view', 'menuHeight');
					await this.getElRect('u-tab-item', 'menuItemHeight');
				}
				// 将菜单菜单活动item垂直居中
				this.scrollTop = id * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
				//重置数据
				this.goodsList = []
				this.page = 1
				this.search_keyword = ""
				//获取切换数据
				this.category_id = id
				this.getGoodsList()
			},
			// 获取一个目标元素的高度
			getElRect(elClass, dataVal) {
				new Promise((resolve, reject) => {
					const query = uni.createSelectorQuery().in(this);
					query.select('.' + elClass).fields({size: true},res => {
						// 如果节点尚未生成，res值为null，循环调用执行
						if(!res) {
							setTimeout(() => {
								this.getElRect(elClass);
							}, 10);
							return ;
						}
						this[dataVal] = res.height;
					}).exec();
				})
			}
		}
	}
</script>

<style lang="scss" scoped>
	.u-wrap {
		height: calc(100vh);
		/* #ifdef H5 */
		height: calc(100vh - var(--window-top));
		/* #endif */
		display: flex;
		flex-direction: column;
	}

	.u-search-box {
		padding: 18rpx 30rpx;
	}

	.u-menu-wrap {
		flex: 1;
		display: flex;
		overflow: hidden;
	}

	.u-search-inner {
		background-color: rgb(234, 234, 234);
		border-radius: 100rpx;
		display: flex;
		align-items: center;
		padding: 10rpx 16rpx;
	}

	.u-search-text {
		font-size: 26rpx;
		color: $u-tips-color;
		margin-left: 10rpx;
	}

	.u-tab-view {
		width: 200rpx;
		height: 100%;
	}

	.u-tab-item {
		height: 110rpx;
		background: #f6f6f6;
		box-sizing: border-box;
		display: flex;
		align-items: center;
		justify-content: center;
		font-size: 26rpx;
		color: #444;
		font-weight: 400;
		line-height: 1;
		padding: 0 20rpx;
	}
	.u-tab-title{
		background: rgba(0,0,0,.3);
		color: white;
		font-size: 30rpx;
		font-weight: 900;
		
	}
	
	.u-tab-item-active {
		position: relative;
		color: #000;
		font-size: 30rpx;
		font-weight: 600;
		background: #fff;
	}
	
	.u-tab-item-active::before {
		content: "";
		position: absolute;
		border-left: 4px solid $u-type-primary;
		height: 32rpx;
		left: 0;
		top: 39rpx;
	}

	.u-tab-view {
		height: 100%;
	}
	
	.right-box {
		background-color: rgb(250, 250, 250);
	}
	
	.page-view {
		padding: 16rpx;
	}
	
	.class-item {
		margin-bottom: 30rpx;
		background-color: #fff;
		padding: 16rpx;
		border-radius: 8rpx;
	}
	
	.item-title {
		font-size: 26rpx;
		color: $u-main-color;
		font-weight: bold;
	}
	
	.item-menu-name {
		font-weight: normal;
		font-size: 24rpx;
		color: $u-main-color;
	}
	
	.item-container {
		display: flex;
		flex-wrap: wrap;
		padding: 20rpx;
	}
	
	.thumb-box {
		width: 50%;
		display: flex;
		align-items: center;
		justify-content: center;
		flex-direction: column;
		margin-top: 20rpx;
		padding: 20rpx 0;
	}
	
	.item-menu-image {
		width: 120rpx;
		height: 120rpx;
	}
</style>
